Snowmobiles are designed to operate on different kinds of ice and snow-covered surfaces. A snowmobile is commonly provided with a flap to help block some of the snow being projected rearward and upward by the track of the snowmobile during its operation and/or to aid cooling of the snowmobile by redirecting the projected snow onto a heat exchanger of the snowmobile.
A snowmobile traveling on deep soft snow sometimes trenches itself when the tracks start to dig in the snow. This effect is sometimes referred to as trenching. Once the snow flap begins to contact the snow, at least some weight of the snowmobile is transferred from the tracks to the snow flap. This is sometimes referred to as jacking. This results in decreased traction of the track with the snow, which may lead to the snowmobile getting stuck in the trench dug in the snow by the track. Sometimes, when the snowmobile is reversing in deep snow, the snow flap is pushed by the snow at the rear of the snowmobile towards the track and this may lead to the snow flap getting caught under the track.